1
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Henry B, Phillips AJ, Sibley LD, Rosenberg A. A combination of four Toxoplasma gondii nuclear-targeted effectors protects against interferon gamma-driven human host cell death. mBio 2024:e0212424. [PMID: 39292011 DOI: 10.1128/mbio.02124-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Accepted: 08/20/2024] [Indexed: 09/19/2024] Open
Abstract
In both mice and humans, Type II interferon gamma (IFNγ) is crucial for the regulation of Toxoplasma gondii (T. gondii) infection, during acute or chronic phases. To thwart this defense, T. gondii secretes protein effectors hindering the host's immune response. For example, T. gondii relies on the MYR translocon complex to deploy soluble dense granule effectors (GRAs) into the host cell cytosol or nucleus. Recent genome-wide loss-of-function screens in IFNγ-primed primary human fibroblasts identified MYR translocon components as crucial for parasite resistance against IFNγ-driven vacuole clearance. However, these screens did not pinpoint specific MYR-dependent GRA proteins responsible for IFNγ signaling blockade, suggesting potential functional redundancy. Our study reveals that T. gondii depends on the MYR translocon complex to prevent parasite premature egress and host cell death in human cells stimulated with IFNγ post-infection, a unique phenotype observed in various human cell lines but not in murine cells. Intriguingly, inhibiting parasite egress did not prevent host cell death, indicating this mechanism is distinct from those described previously. Genome-wide loss-of-function screens uncovered TgIST, GRA16, GRA24, and GRA28 as effectors necessary for a complete block of IFNγ response. GRA24 and GRA28 directly influenced IFNγ-driven transcription, GRA24's action depended on its interaction with p38 MAPK, while GRA28 disrupted histone acetyltransferase activity of CBP/p300. Given the intricate nature of the immune response to T. gondii, it appears that the parasite has evolved equally elaborate mechanisms to subvert IFNγ signaling, extending beyond direct interference with the JAK/STAT1 pathway, to encompass other signaling pathways as well.IMPORTANCEToxoplasma gondii, an intracellular parasite, affects nearly one-third of the global human population, posing significant risks for immunocompromised patients and infants infected in utero. In murine models, the core mechanisms of IFNγ-mediated immunity against T. gondii are consistently preserved, showcasing a remarkable conservation of immune defense mechanisms. In humans, the recognized restriction mechanisms vary among cell types, lacking a universally applicable mechanism. This difference underscores a significant variation in the genes employed by T. gondii to shield itself against the IFNγ response in human vs murine cells. Here, we identified a specific combination of four parasite-secreted effectors deployed into the host cell nucleus, disrupting IFNγ signaling. This disruption is crucial in preventing premature egress of the parasite and host cell death. Notably, this phenotype is exclusive to human cells, highlighting the intricate and unique mechanisms T. gondii employs to modulate host responses in the human cellular environment.
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Affiliation(s)
- Brittany Henry
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Aubrey J Phillips
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alex Rosenberg
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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2
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Zheng XN, Li TT, Elsheikha HM, Wang M, Sun LX, Wu XJ, Fu BQ, Zhu XQ, Wang JL. GRA47 is important for the morphology and permeability of the parasitophorous vacuole in Toxoplasma gondii. Int J Parasitol 2024; 54:583-596. [PMID: 38936501 DOI: 10.1016/j.ijpara.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 05/13/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024]
Abstract
Establishing an intact intracellular parasitophorous vacuole (PV) that enables efficient nutrient uptake and protein trafficking is essential for the survival and proliferation of Toxoplasma gondii. Although the PV membrane (PVM)-localized dense granule protein 17 (GRA17) and GRA23 mediate the permeability of the PVM to small molecules, including nutrient uptake and excretion of metabolic by-products, the molecular mechanism by which T. gondii acquires nutrients remains unclear. In this study, we showed that the secreted protein GRA47 contributed to normal PV morphology, PVM permeability to small molecules, growth, and virulence in T. gondii. Co-immunoprecipitation analysis demonstrated potential interaction of GRA47 with GRA72, and the loss of GRA72 affected PV morphology, parasite growth and infectivity. To investigate the biological relationship among GRA47, GRA72, GRA17 and GRA23, attempts were made to construct strains with double gene deletion and overexpressing strains. Only Δgra23Δgra72 was successfully constructed. This strain exhibited a significant increase in the proportion of aberrant PVs compared with the Δgra23 strain. Overexpressing one of the three related GRAs partially rescued PVs with aberrant morphology in Δgra47, Δgra72 and Δgra17, while the expression of the Plasmodium falciparum PVM protein PfExp2, an ortholog of GRA17 and GRA23, fully rescued the PV morphological defect in all three Δgra strains. These results suggest that these GRA proteins may not be functionally redundant but rather work in different ways to regulate nutrient acquisition. These findings highlight the versatility of the nutrient uptake mechanisms in T. gondii, which may contribute to the parasite's remarkable ability to grow in different cellular niches in a very broad range of hosts.
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Affiliation(s)
- Xiao-Nan Zheng
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Ting-Ting Li
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Meng Wang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Li-Xiu Sun
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Xiao-Jing Wu
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Bao-Quan Fu
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Xing-Quan Zhu
- Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China.
| | - Jin-Lei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China.
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3
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Ten Hoeve AL, Rodriguez ME, Säflund M, Michel V, Magimel L, Ripoll A, Yu T, Hakimi MA, Saeij JPJ, Ozata DM, Barragan A. Hypermigration of macrophages through the concerted action of GRA effectors on NF-κB/p38 signaling and host chromatin accessibility potentiates Toxoplasma dissemination. mBio 2024:e0214024. [PMID: 39207098 DOI: 10.1128/mbio.02140-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Accepted: 08/06/2024] [Indexed: 09/04/2024] Open
Abstract
Mononuclear phagocytes facilitate the dissemination of the obligate intracellular parasite Toxoplasma gondii. Here, we report how a set of secreted parasite effector proteins from dense granule organelles (GRA) orchestrates dendritic cell-like chemotactic and pro-inflammatory activation of parasitized macrophages. These effects enabled efficient dissemination of the type II T. gondii lineage, a highly prevalent genotype in humans. We identify novel functions for effectors GRA15 and GRA24 in promoting CCR7-mediated macrophage chemotaxis by acting on NF-κB and p38 mitogen-activated protein kinase signaling pathways, respectively, with contributions by GRA16/18 and counter-regulation by effector TEEGR. Furthermore, GRA28 boosted chromatin accessibility and GRA15/24/NF-κB-dependent transcription at the Ccr7 gene locus in primary macrophages. In vivo, adoptively transferred macrophages infected with wild-type T. gondii outcompeted macrophages infected with a GRA15/24 double mutant in migrating to secondary organs in mice. The data show that T. gondii, rather than being passively shuttled, actively promotes its dissemination by inducing a finely regulated pro-migratory state in parasitized human and murine phagocytes via co-operating polymorphic GRA effectors. IMPORTANCE Intracellular pathogens can hijack the cellular functions of infected host cells to their advantage, for example, for intracellular survival and dissemination. However, how microbes orchestrate the hijacking of complex cellular processes, such as host cell migration, remains poorly understood. As such, the common parasite Toxoplasma gondii actively invades the immune cells of humans and other vertebrates and modifies their migratory properties. Here, we show that the concerted action of a number of secreted effector proteins from the parasite, principally GRA15 and GRA24, acts on host cell signaling pathways to activate chemotaxis. Furthermore, the protein effector GRA28 selectively acted on chromatin accessibility in the host cell nucleus to selectively boost host gene expression. The joint activities of GRA effectors culminated in pro-migratory signaling within the infected phagocyte. We provide a molecular framework delineating how T. gondii can orchestrate a complex biological phenotype, such as the migratory activation of phagocytes to boost dissemination.
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Affiliation(s)
- Arne L Ten Hoeve
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Matias E Rodriguez
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Martin Säflund
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Valentine Michel
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Lucas Magimel
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Albert Ripoll
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Tianxiong Yu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology, and Immunology, University of California Davis, Davis, California, USA
| | - Deniz M Ozata
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Wang X, Qu L, Chen J, Hu K, Zhou Z, Zhang J, An Y, Zheng J. Rhoptry proteins affect the placental barrier in the context of Toxoplasma gondii infection: Signaling pathways and functions. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 280:116567. [PMID: 38850700 DOI: 10.1016/j.ecoenv.2024.116567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/21/2024] [Accepted: 06/05/2024] [Indexed: 06/10/2024]
Abstract
Toxoplasma gondii is an opportunistic and pathogenic obligate intracellular parasitic protozoan that is widespread worldwide and can infect most warm-blooded animals, seriously endangering human health and affecting livestock production. Toxoplasmosis caused by T. gondii infection has different clinical manifestations, which are mainly determined by the virulence of T. gondii and host differences. Among the manifestations of this condition, abortion, stillbirth, and fetal malformation can occur if a woman is infected with T. gondii in early pregnancy. Here, we discuss how the T. gondii rhoptry protein affects host pregnancy outcomes and speculate on the related signaling pathways involved. The effects of rhoptry proteins of T. gondii on the placental barrier are complex. Rhoptry proteins not only regulate interferon-regulated genes (IRGs) to ensure the survival of parasites in activated cells but also promote the spread of worms in tissues and the invasive ability of the parasites. The functions of these rhoptry proteins and the associated signaling pathways highlight relevant mechanisms by which Toxoplasma crosses the placental barrier and influences fetal development and will guide future studies to uncover the complexity of the host-pathogen interactions.
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Affiliation(s)
- Xinlei Wang
- Department of Clinical Laboratory, The Second Hospital of Jilin University, Changchun, China
| | - Lai Qu
- Department of Intensive Care Unit, First Hospital of Jilin University, Changchun, China
| | - Jie Chen
- Institute of Theoretical Chemistry, Jilin University, Changchun, China
| | - Kaisong Hu
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Zhengjie Zhou
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Jiaqi Zhang
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Yiming An
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Jingtong Zheng
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, China.
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5
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Sadr S, Ahmadi Simab P, Niazi M, Yousefsani Z, Lotfalizadeh N, Hajjafari A, Borji H. Anti-inflammatory and immunomodulatory effects of mesenchymal stem cell therapy on parasitic drug resistance. Expert Rev Anti Infect Ther 2024; 22:435-451. [PMID: 38804866 DOI: 10.1080/14787210.2024.2360684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/23/2024] [Indexed: 05/29/2024]
Abstract
INTRODUCTION The emergence of antiparasitic drug resistance poses a concerning threat to animals and humans. Mesenchymal Stem Cells (MSCs) have been widely used to treat infections in humans, pets, and livestock. Although this is an emerging field of study, the current review outlines possible mechanisms and examines potential synergism in combination therapies and the possible harmful effects of such an approach. AREAS COVERED The present study delved into the latest pre-clinical research on utilizing MSCs to treat parasitic infections. As per investigations, the introduction of MSCs to patients grappling with parasitic diseases like schistosomiasis, malaria, cystic echinococcosis, toxoplasmosis, leishmaniasis, and trypanosomiasis has shown a reduction in parasite prevalence. This intervention also alters the levels of both pro- and anti-inflammatory cytokines. Furthermore, the combined administration of MSCs and antiparasitic drugs has demonstrated enhanced efficacy in combating parasites and modulating the immune response. EXPERT OPINION Mesenchymal stem cells are a potential solution for addressing parasitic drug resistance. This is mainly because of their remarkable immunomodulatory abilities, which can potentially help combat parasites' resistance to drugs.
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Affiliation(s)
- Soheil Sadr
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Pouria Ahmadi Simab
- Department of Pathobiology, Faculty of Veterinary Medicine, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran
| | - Mahta Niazi
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Zahra Yousefsani
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Narges Lotfalizadeh
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Ashkan Hajjafari
- Department of Pathobiology, Faculty of Veterinary Medicine, Islamic Azad University, Science and Research Branch, Tehran, Iran
| | - Hassan Borji
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
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6
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Ten Hoeve AL, Rodriguez ME, Säflund M, Michel V, Magimel L, Ripoll A, Yu T, Hakimi MA, Saeij JPJ, Ozata DM, Barragan A. Hypermigration of macrophages through the concerted action of GRA effectors on NF-κB/p38 signaling and host chromatin accessibility potentiates Toxoplasma dissemination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579146. [PMID: 38370679 PMCID: PMC10871220 DOI: 10.1101/2024.02.06.579146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Mononuclear phagocytes facilitate the dissemination of the obligate intracellular parasite Toxoplasma gondii. Here, we report how a set of secreted parasite effector proteins from dense granule organelles (GRA) orchestrates dendritic cell-like chemotactic and pro-inflammatory activation of parasitized macrophages. These effects enabled efficient dissemination of the type II T. gondii lineage, a highly prevalent genotype in humans. We identify novel functions for effectors GRA15 and GRA24 in promoting CCR7-mediated macrophage chemotaxis by acting on NF-κB and p38 MAPK signaling pathways, respectively, with contributions of GRA16/18 and counter-regulation by effector TEEGR. Further, GRA28 boosted chromatin accessibility and GRA15/24/NF-κB-dependent transcription at the Ccr7 gene locus in primary macrophages. In vivo, adoptively transferred macrophages infected with wild-type T. gondii outcompeted macrophages infected with a GRA15/24 double mutant in migrating to secondary organs in mice. The data show that T. gondii, rather than being passively shuttled, actively promotes its dissemination by inducing a finely regulated pro-migratory state in parasitized human and murine phagocytes via co-operating polymorphic GRA effectors.
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Affiliation(s)
- Arne L Ten Hoeve
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Matias E Rodriguez
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Martin Säflund
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Valentine Michel
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Lucas Magimel
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Albert Ripoll
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Tianxiong Yu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology, and Immunology, University of California Davis, Davis, CA 95616 California, USA
| | - Deniz M Ozata
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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7
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Seizova S, Ferrel A, Boothroyd J, Tonkin CJ. Toxoplasma protein export and effector function. Nat Microbiol 2024; 9:17-28. [PMID: 38172621 DOI: 10.1038/s41564-023-01563-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 11/16/2023] [Indexed: 01/05/2024]
Abstract
Toxoplasma gondii is a single-celled eukaryotic parasite with a considerable host range that must invade the cells of warm-blooded hosts to survive and replicate. The challenges and opportunities that such a strategy represent have been met by the evolution of effectors that are delivered into host cells, counter host defences and co-opt host cell functions for their own purposes. These effectors are delivered in two waves using distinct machinery for each. In this Review, we focus on understanding the architecture of these protein-export systems and how their protein cargo is recognized and selected. We discuss the recent findings on the role that host manipulation has in latent Toxoplasma infections. We also discuss how these recent findings compare to protein export in the related Plasmodium spp. (the causative agent of malaria) and how this can inform our understanding of host manipulation in the larger Apicomplexa phylum and its evolution.
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Affiliation(s)
- Simona Seizova
- School of Life Sciences, The University of Dundee, Dundee, UK
| | - Abel Ferrel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA
| | - John Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA.
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
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Sitaraman R. Subversion from Within and Without: Effector Molecule Transfer from Obligate Intracellular Apicomplexan Parasites to Human Host Cells. Results Probl Cell Differ 2024; 73:521-535. [PMID: 39242391 DOI: 10.1007/978-3-031-62036-2_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2024]
Abstract
Intracellular protozoan pathogens have to negotiate the internal environment of the host cell they find themselves in, as well as manipulate the host cell to ensure their own survival, replication, and dissemination. The transfer of key effector molecules from the pathogen to the host cell is crucial to this interaction and is technically more demanding to study as compared to an extracellular pathogen. While several effector molecules have been identified, the mechanisms and conditions underlying their transfer to the host cell remain partly or entirely unknown. Improvements in experimental systems have revealed tantalizing details of such intercellular transfer, which form the subject of this chapter.
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Henry B, Sibley LD, Rosenberg A. A Combination of Four Nuclear Targeted Effectors Protects Toxoplasma Against Interferon Gamma Driven Human Host Cell Death During Acute Infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.24.573224. [PMID: 38234811 PMCID: PMC10793417 DOI: 10.1101/2023.12.24.573224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
In both mice and humans, Type II interferon-gamma (IFNγ) is crucial for regulation of Toxoplasma gondii (T. gondii) infection, during acute or chronic phases. To thwart this defense, T. gondii secretes protein effectors hindering the hosťs immune response. For example, T. gondii relies on the MYR translocon complex to deploy soluble dense granule effectors (GRAs) into the host cell cytosol or nucleus. Recent genome-wide loss-of-function screens in IFNγ-primed primary human fibroblasts identified MYR translocon components as crucial for parasite resistance against IFNγ driven vacuole clearance. However, these screens did not pinpoint specific MYR-dependent GRA proteins responsible for IFNγ signaling blockade, suggesting potential functional redundancy. Our study reveals that T. gondii depends on the MYR translocon complex to prevent host cell death and parasite premature egress in human cells stimulated with IFNγ postinfection, a unique phenotype observed in various human cell lines but not in murine cells. Intriguingly, inhibiting parasite egress did not prevent host cell death, indicating this mechanism is distinct from those described previously. Genome-wide loss-of-function screens uncovered TgIST, GRA16, GRA24, and GRA28 as effectors necessary for a complete block of IFNγ response. GRA24 and GRA28 directly influenced IFNγ driven transcription, GRA24's action depended on its interaction with p38 MAPK, while GRA28 disrupted histone acetyltransferase activity of CBP/p300. Given the intricate nature of the immune response to T. gondii, it appears that the parasite has evolved equally elaborate mechanisms to subvert IFNγ signaling, extending beyond direct interference with the JAK/STAT1 pathway, to encompass other signaling pathways as well.
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Affiliation(s)
- Brittany Henry
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Alex Rosenberg
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
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10
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Butterworth S, Kordova K, Chandrasekaran S, Thomas KK, Torelli F, Lockyer EJ, Edwards A, Goldstone R, Koshy AA, Treeck M. High-throughput identification of Toxoplasma gondii effector proteins that target host cell transcription. Cell Host Microbe 2023; 31:1748-1762.e8. [PMID: 37827122 DOI: 10.1016/j.chom.2023.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/04/2023] [Accepted: 09/07/2023] [Indexed: 10/14/2023]
Abstract
Intracellular pathogens and other endosymbionts reprogram host cell transcription to suppress immune responses and recalibrate biosynthetic pathways. This reprogramming is critical in determining the outcome of infection or colonization. We combine pooled CRISPR knockout screening with dual host-microbe single-cell RNA sequencing, a method we term dual perturb-seq, to identify the molecular mediators of these transcriptional interactions. Applying dual perturb-seq to the intracellular pathogen Toxoplasma gondii, we are able to identify previously uncharacterized effector proteins and directly infer their function from the transcriptomic data. We show that TgGRA59 contributes to the export of other effector proteins from the parasite into the host cell and identify an effector, TgSOS1, that is necessary for sustained host STAT6 signaling and thereby contributes to parasite immune evasion and persistence. Together, this work demonstrates a tool that can be broadly adapted to interrogate host-microbe transcriptional interactions and reveal mechanisms of infection and immune evasion.
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Affiliation(s)
- Simon Butterworth
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Kristina Kordova
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | | | | | - Francesca Torelli
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Eloise J Lockyer
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Amelia Edwards
- Advanced Sequencing Facility, The Francis Crick Institute, London NW1 1AT, UK
| | - Robert Goldstone
- Advanced Sequencing Facility, The Francis Crick Institute, London NW1 1AT, UK
| | - Anita A Koshy
- BIO5 Institute, University of Arizona, Tucson, AZ 85719, USA; Department of Immunobiology, University of Arizona, Tucson, AZ 85719, USA; Department of Neurology, University of Arizona, Tucson, AZ 85719, USA
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Cell Biology of Host-Pathogen Interaction Laboratory, Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal.
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Ferrel A, Romano J, Panas MW, Coppens I, Boothroyd JC. Host MOSPD2 enrichment at the parasitophorous vacuole membrane varies between Toxoplasma strains and involves complex interactions. mSphere 2023; 8:e0067022. [PMID: 37341482 PMCID: PMC10449529 DOI: 10.1128/msphere.00670-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/25/2023] [Indexed: 06/22/2023] Open
Abstract
Toxoplasma gondii is an obligate, intracellular parasite. Infection of a cell produces a unique niche for the parasite named the parasitophorous vacuole (PV) initially composed of host plasma membrane invaginated during invasion. The PV and its membrane (parasitophorous vacuole membrane [PVM]) are subsequently decorated with a variety of parasite proteins allowing the parasite to optimally grow in addition to manipulate host processes. Recently, we reported a proximity-labeling screen at the PVM-host interface and identified host endoplasmic reticulum (ER)-resident motile sperm domain-containing protein 2 (MOSPD2) as being enriched at this location. Here we extend these findings in several important respects. First, we show that the extent and pattern of host MOSPD2 association with the PVM differ dramatically in cells infected with different strains of Toxoplasma. Second, in cells infected with Type I RH strain, the MOSPD2 staining is mutually exclusive with regions of the PVM that associate with mitochondria. Third, immunoprecipitation and liquid chromatography tandem mass spectrometry (LC-MS/MS) with epitope-tagged MOSPD2-expressing host cells reveal strong enrichment of several PVM-localized parasite proteins, although none appear to play an essential role in MOSPD2 association. Fourth, most MOSPD2 associating with the PVM is newly translated after infection of the cell and requires the major functional domains of MOSPD2, identified as the CRAL/TRIO domain and tail anchor, although these domains were not sufficient for PVM association. Lastly, ablation of MOSPD2 results in, at most, a modest impact on Toxoplasma growth in vitro. Collectively, these studies provide new insight into the molecular interactions involving MOSPD2 at the dynamic interface between the PVM and the host cytosol. IMPORTANCE Toxoplasma gondii is an intracellular pathogen that lives within a membranous vacuole inside of its host cell. This vacuole is decorated by a variety of parasite proteins that allow it to defend against host attack, acquire nutrients, and interact with the host cell. Recent work identified and validated host proteins enriched at this host-pathogen interface. Here, we follow up on one candidate named MOSPD2 shown to be enriched at the vacuolar membrane and describe it as having a dynamic interaction at this location depending on a variety of factors. Some of these include the presence of host mitochondria, intrinsic domains of the host protein, and whether translation is active. Importantly, we show that MOSPD2 enrichment at the vacuole membrane differs between strains indicating active involvement of the parasite with this phenotype. Altogether, these results shed light on the mechanism and role of protein associations in the host-pathogen interaction.
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Affiliation(s)
- Abel Ferrel
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Julia Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Michael W. Panas
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - John C. Boothroyd
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
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12
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Lockyer EJ, Torelli F, Butterworth S, Song OR, Howell S, Weston A, East P, Treeck M. A heterotrimeric complex of Toxoplasma proteins promotes parasite survival in interferon gamma-stimulated human cells. PLoS Biol 2023; 21:e3002202. [PMID: 37459303 PMCID: PMC10373997 DOI: 10.1371/journal.pbio.3002202] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/27/2023] [Accepted: 06/16/2023] [Indexed: 07/28/2023] Open
Abstract
Toxoplasma gondii secretes protein effectors to subvert the human immune system sufficiently to establish a chronic infection. Relative to murine infections, little is known about which parasite effectors disarm human immune responses. Here, we used targeted CRISPR screening to identify secreted protein effectors required for parasite survival in IFNγ-activated human cells. Independent screens were carried out using 2 Toxoplasma strains that differ in virulence in mice, leading to the identification of effectors required for survival in IFNγ-activated human cells. We identify the secreted protein GRA57 and 2 other proteins, GRA70 and GRA71, that together form a complex which enhances the ability of parasites to persist in IFNγ-activated human foreskin fibroblasts (HFFs). Components of the protein machinery required for export of Toxoplasma proteins into the host cell were also found to be important for parasite resistance to IFNγ in human cells, but these export components function independently of the identified protein complex. Host-mediated ubiquitination of the parasite vacuole has previously been associated with increased parasite clearance from human cells, but we find that vacuoles from GRA57, GRA70, and GRA71 knockout strains are surprisingly less ubiquitinated by the host cell. We hypothesise that this is likely a secondary consequence of deletion of the complex, unlinked to the IFNγ resistance mediated by these effectors.
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Affiliation(s)
- Eloise J Lockyer
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Francesca Torelli
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Simon Butterworth
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Ok-Ryul Song
- High-Throughput Screening Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Steven Howell
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Anne Weston
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Philip East
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
- Cell Biology of Host-Pathogen Interaction Laboratory, Instituto Gulbenkian Ciência, Oeiras, Portugal
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13
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Krishnamurthy S, Maru P, Wang Y, Bitew MA, Mukhopadhyay D, Yamaryo-Botté Y, Paredes-Santos TC, Sangaré LO, Swale C, Botté CY, Saeij JPJ. CRISPR Screens Identify Toxoplasma Genes That Determine Parasite Fitness in Interferon Gamma-Stimulated Human Cells. mBio 2023; 14:e0006023. [PMID: 36916910 PMCID: PMC10128063 DOI: 10.1128/mbio.00060-23] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 01/11/2023] [Indexed: 03/16/2023] Open
Abstract
Toxoplasma virulence depends on its ability to evade or survive the toxoplasmacidal mechanisms induced by interferon gamma (IFNγ). While many Toxoplasma genes involved in the evasion of the murine IFNγ response have been identified, genes required to survive the human IFNγ response are largely unknown. In this study, we used a genome-wide loss-of-function screen to identify Toxoplasma genes important for parasite fitness in IFNγ-stimulated primary human fibroblasts. We generated gene knockouts for the top six hits from the screen and confirmed their importance for parasite growth in IFNγ-stimulated human fibroblasts. Of these six genes, three have homology to GRA32, localize to dense granules, and coimmunoprecipitate with each other and GRA32, suggesting they might form a complex. Deletion of individual members of this complex leads to early parasite egress in IFNγ-stimulated cells. Thus, prevention of early egress is an important Toxoplasma fitness determinant in IFNγ-stimulated human cells. IMPORTANCE Toxoplasma infection causes serious complications in immunocompromised individuals and in the developing fetus. During infection, certain immune cells release a protein called interferon gamma that activates cells to destroy the parasite or inhibit its growth. While most Toxoplasma parasites are cleared by this immune response, some can survive by blocking or evading the IFNγ-induced restrictive environment. Many Toxoplasma genes that determine parasite survival in IFNγ-activated murine cells are known but parasite genes conferring fitness in IFNγ-activated human cells are largely unknown. Using a Toxoplasma adapted genome-wide loss-of-function screen, we identified many Toxoplasma genes that determine parasite fitness in IFNγ-activated human cells. The gene products of four top hits play a role in preventing early parasite egress in IFNγ-stimulated human cells. Understanding how IFNγ-stimulated human cells inhibit Toxoplasma growth and how Toxoplasma counteracts this, could lead to the development of novel therapeutics.
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Affiliation(s)
- Shruthi Krishnamurthy
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Parag Maru
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Yifan Wang
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Mebratu A. Bitew
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Debanjan Mukhopadhyay
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Yoshiki Yamaryo-Botté
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Batiment Jean Roget, Grenoble, France
| | - Tatiana C. Paredes-Santos
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Lamba O. Sangaré
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences (IAB), INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Cyrille Y. Botté
- Apicolipid Team, Institute for Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Batiment Jean Roget, Grenoble, France
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
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14
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Overview of Apoptosis, Autophagy, and Inflammatory Processes in Toxoplasma gondii Infected Cells. Pathogens 2023; 12:pathogens12020253. [PMID: 36839525 PMCID: PMC9966443 DOI: 10.3390/pathogens12020253] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 02/08/2023] Open
Abstract
Toxoplasma gondii (T. gondii) is an obligate intracellular parasite. During the parasitic invasion, T. gondii creates a parasitophorous vacuole, which enables the modulation of cell functions, allowing its replication and host infection. It has effective strategies to escape the immune response and reach privileged immune sites and remain inactive in a controlled environment in tissue cysts. This current review presents the factors that affect host cells and the parasite, as well as changes in the immune system during host cell infection. The secretory organelles of T. gondii (dense granules, micronemes, and rhoptries) are responsible for these processes. They are involved with proteins secreted by micronemes and rhoptries (MIC, AMA, and RONs) that mediate the recognition and entry into host cells. Effector proteins (ROP and GRA) that modify the STAT signal or GTPases in immune cells determine their toxicity. Interference byhost autonomous cells during parasitic infection, gene expression, and production of microbicidal molecules such as reactive oxygen species (ROS) and nitric oxide (NO), result in the regulation of cell death. The high level of complexity in host cell mechanisms prevents cell death in its various pathways. Many of these abilities play an important role in escaping host immune responses, particularly by manipulating the expression of genes involved in apoptosis, necrosis, autophagy, and inflammation. Here we present recent works that define the mechanisms by which T. gondii interacts with these processes in infected host cells.
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15
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A. PORTES JULIANA, C. VOMMARO ROSSIANE, AYRES CALDAS LUCIO, S. MARTINS-DUARTE ERICA. Intracellular life of protozoan Toxoplasma gondii: Parasitophorous vacuole establishment and survival strategies. BIOCELL 2023. [DOI: 10.32604/biocell.2023.026629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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16
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Toxoplasma gondii Dissemination in the Brain Is Facilitated by Infiltrating Peripheral Immune Cells. mBio 2022; 13:e0283822. [PMID: 36445695 PMCID: PMC9765297 DOI: 10.1128/mbio.02838-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Despite recent advances in our understanding of pathogenic access to the central nervous system (CNS), the mechanisms by which intracellular pathogens disseminate within the dense cellular network of neural tissue remain poorly understood. To address this issue, longitudinal analysis of Toxoplasma gondii dissemination in the brain was conducted using 2-photon imaging through a cranial window in living mice that transgenically express enhanced green fluorescent protein (eGFP)-claudin-5. Extracellular T. gondii parasites were observed migrating slowly (1.37 ± 1.28 μm/min) and with low displacement within the brain. In contrast, a population of highly motile infected cells transported vacuoles of T. gondii significantly faster (6.30 ± 3.09 μm/min) and with a higher displacement than free parasites. Detailed analysis of microglial dynamics using CX3CR1-GFP mice revealed that T. gondii-infected microglia remained stationary, and infection did not increase the extension/retraction of microglial processes. The role of infiltrating immune cells in shuttling T. gondii was examined by labeling of peripheral hematopoietic cells with anti-CD45 antibody. Infected CD45+ cells were found crawling along the CNS vessel walls and trafficked T. gondii within the brain parenchyma at significantly higher speeds (3.35 ± 1.70 μm/min) than extracellular tachyzoites. Collectively, these findings highlight a dual role for immune cells in neuroprotection and in facilitating parasite dissemination within the brain. IMPORTANCE T. gondii is a foodborne parasite that infects the brain and can cause fatal encephalitis in immunocompromised individuals. However, there is a limited understanding of how the parasites disseminate through the brain and evade immune clearance. We utilized intravital imaging to visualize extracellular T. gondii tachyzoites and infected cells migrating within the infected mouse brain during acute infection. The infection of motile immune cells infiltrating the brain from the periphery significantly increased the dissemination of T. gondii in the brain compared to that of free parasites migrating using their own motility: the speed and displacement of these infected cells would enable them to cover nearly 1 cm of distance per day! Among the infiltrating cells, T. gondii predominantly infected monocytes and CD8+ T cells, indicating that the parasite can hijack immune cells that are critical for controlling the infection in order to enhance their dissemination within the brain.
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17
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Dogga SK, Lunghi M, Maco B, Li J, Claudi B, Marq JB, Chicherova N, Kockmann T, Bumann D, Hehl AB, Soldati-Favre D, Hammoudi PM. Importance of aspartyl protease 5 in the establishment of the intracellular niche during acute and chronic infection of Toxoplasma gondii. Mol Microbiol 2022; 118:601-622. [PMID: 36210525 DOI: 10.1111/mmi.14987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022]
Abstract
Virulence and persistence of the obligate intracellular parasite Toxoplasma gondii involve the secretion of effector proteins belonging to the family of dense granule proteins (GRAs) that act notably as modulators of the host defense mechanisms and participate in cyst wall formation. The subset of GRAs residing in the parasitophorous vacuole (PV) or exported into the host cell, undergo proteolytic cleavage in the Golgi upon the action of the aspartyl protease 5 (ASP5). In tachyzoites, ASP5 substrates play central roles in the morphology of the PV and the export of effectors across the translocon complex MYR1/2/3. Here, we used N-terminal amine isotopic labeling of substrates to identify novel ASP5 cleavage products by comparing the N-terminome of wild-type and Δasp5 lines in tachyzoites and bradyzoites. Validated substrates reside within the PV or PVM in an ASP5-dependent manner. Remarkably, Δasp5 bradyzoites are impaired in the formation of the cyst wall in vitro and exhibit a considerably reduced cyst burden in chronically infected animals. More specifically two-photon serial tomography of infected mouse brains revealed a comparatively reduced number and size of the cysts throughout the establishment of persistence in the absence of ASP5.
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Affiliation(s)
- Sunil Kumar Dogga
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Matteo Lunghi
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Jiagui Li
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Beatrice Claudi
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Jean-Baptiste Marq
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Natalia Chicherova
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Tobias Kockmann
- Functional Genomics Center Zurich, ETH Zurich/University of Zurich, Zurich, Switzerland
| | - Dirk Bumann
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Adrian B Hehl
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Pierre-Mehdi Hammoudi
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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18
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Ten Hoeve AL, Braun L, Rodriguez ME, Olivera GC, Bougdour A, Belmudes L, Couté Y, Saeij JPJ, Hakimi MA, Barragan A. The Toxoplasma effector GRA28 promotes parasite dissemination by inducing dendritic cell-like migratory properties in infected macrophages. Cell Host Microbe 2022; 30:1570-1588.e7. [PMID: 36309013 PMCID: PMC9710525 DOI: 10.1016/j.chom.2022.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/26/2022] [Accepted: 10/03/2022] [Indexed: 11/03/2022]
Abstract
Upon pathogen detection, macrophages normally stay sessile in tissues while dendritic cells (DCs) migrate to secondary lymphoid tissues. The obligate intracellular protozoan Toxoplasma gondii exploits the trafficking of mononuclear phagocytes for dissemination via unclear mechanisms. We report that, upon T. gondii infection, macrophages initiate the expression of transcription factors normally attributed to DCs, upregulate CCR7 expression with a chemotactic response, and perform systemic migration when adoptively transferred into mice. We show that parasite effector GRA28, released by the MYR1 secretory pathway, cooperates with host chromatin remodelers in the host cell nucleus to drive the chemotactic migration of parasitized macrophages. During in vivo challenge studies, bone marrow-derived macrophages infected with wild-type T. gondii outcompeted those challenged with MYR1- or GRA28-deficient strains in migrating and reaching secondary organs. This work reveals how an intracellular parasite hijacks chemotaxis in phagocytes and highlights a remarkable migratory plasticity in differentiated cells of the mononuclear phagocyte system.
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Affiliation(s)
- Arne L Ten Hoeve
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Laurence Braun
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Matias E Rodriguez
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Gabriela C Olivera
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Alexandre Bougdour
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Lucid Belmudes
- Univ. Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Yohann Couté
- Univ. Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology, and Immunology, University of California Davis, Davis, CA 95616, USA
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France.
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden.
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19
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Griffith MB, Pearce CS, Heaslip AT. Dense granule biogenesis, secretion, and function in Toxoplasma gondii. J Eukaryot Microbiol 2022; 69:e12904. [PMID: 35302693 PMCID: PMC9482668 DOI: 10.1111/jeu.12904] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite and the causative agent of Toxoplasmosis. A key to understanding and treating the disease lies with determining how the parasite can survive and replicate within cells of its host. Proteins released from specialized secretory vesicles, named the dense granules (DGs), have diverse functions that are critical for adapting the intracellular environment, and are thus key to survival and pathogenicity. In this review, we describe the current understanding and outstanding questions regarding dense granule biogenesis, trafficking, and regulation of secretion. In addition, we provide an overview of dense granule protein ("GRA") function upon secretion, with a focus on proteins that have recently been identified.
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Affiliation(s)
- Michael B Griffith
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Camille S Pearce
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Aoife T Heaslip
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
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20
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Sasai M, Yamamoto M. Anti-toxoplasma host defense systems and the parasitic counterdefense mechanisms. Parasitol Int 2022; 89:102593. [DOI: 10.1016/j.parint.2022.102593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 04/12/2022] [Accepted: 04/26/2022] [Indexed: 10/18/2022]
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21
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Silvestre A, Shintre SS, Rachidi N. Released Parasite-Derived Kinases as Novel Targets for Antiparasitic Therapies. Front Cell Infect Microbiol 2022; 12:825458. [PMID: 35252034 PMCID: PMC8893276 DOI: 10.3389/fcimb.2022.825458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
The efficient manipulation of their host cell is an essential feature of intracellular parasites. Most molecular mechanisms governing the subversion of host cell by protozoan parasites involve the release of parasite-derived molecules into the host cell cytoplasm and direct interaction with host proteins. Among these released proteins, kinases are particularly important as they govern the subversion of important host pathways, such as signalling or metabolic pathways. These enzymes, which catalyse the transfer of a phosphate group from ATP onto serine, threonine, tyrosine or histidine residues to covalently modify proteins, are involved in numerous essential biological processes such as cell cycle or transport. Although little is known about the role of most of the released parasite-derived kinases in the host cell, they are examples of kinases hijacking host cellular pathways such as signal transduction or apoptosis, which are essential for immune response evasion as well as parasite survival and development. Here we present the current knowledge on released protozoan kinases and their involvement in host-pathogen interactions. We also highlight the knowledge gaps remaining before considering those kinases - involved in host signalling subversion - as antiparasitic drug targets.
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Affiliation(s)
- Anne Silvestre
- INRAE, Université de Tours, ISP, Nouzilly, France
- *Correspondence: Anne Silvestre, ; Najma Rachidi,
| | - Sharvani Shrinivas Shintre
- INRAE, Université de Tours, ISP, Nouzilly, France
- Institut Pasteur, Université de Paris and INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France
| | - Najma Rachidi
- Institut Pasteur, Université de Paris and INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France
- *Correspondence: Anne Silvestre, ; Najma Rachidi,
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22
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Seizova S, Ruparel U, Garnham AL, Bader SM, Uboldi AD, Coffey MJ, Whitehead LW, Rogers KL, Tonkin CJ. Transcriptional modification of host cells harboring Toxoplasma gondii bradyzoites prevents IFN gamma-mediated cell death. Cell Host Microbe 2021; 30:232-247.e6. [PMID: 34921775 DOI: 10.1016/j.chom.2021.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 10/05/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022]
Abstract
Toxoplasma gondii develops a latent infection in the muscle and central nervous system that acts as a reservoir for acute-stage reactivation in vulnerable patients. Little is understood about how parasites manipulate host cells during latent infection and the impact this has on survival. We show that bradyzoites impart a unique transcriptional signature on infected host cells. Many of these transcriptional changes rely on protein export and result in the suppression of type I interferon (IFN) and IFNγ signaling more so than in acute stages. Loss of the protein export component, MYR1, abrogates transcriptional remodeling and prevents suppression of IFN signaling. Among the exported proteins, the inhibitor of STAT1 transcription (IST) plays a key role in limiting IFNγ signaling in bradyzoites. Furthermore, bradyzoite protein export protects host cells from IFNγ-mediated cell death, even when export is restricted to latent stages. These findings highlight the functional importance of host manipulation in Toxoplasma's bradyzoite stages.
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Affiliation(s)
- Simona Seizova
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia; Wellcome Center for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee DD1 5EH, UK
| | - Ushma Ruparel
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Alexandra L Garnham
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Stefanie M Bader
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Alessandro D Uboldi
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Michael J Coffey
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia; Poseida Therapeutics, San Diego, CA, USA
| | - Lachlan W Whitehead
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Kelly L Rogers
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Christopher J Tonkin
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia.
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23
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Abstract
Toxoplasma gondii is a parasitic protist infecting a wide group of warm-blooded animals, ranging from birds to humans. While this infection is usually asymptomatic in healthy individuals, it can also lead to severe ocular or neurological outcomes in immunocompromised individuals or in developing fetuses. This obligate intracellular parasite has the ability to infect a considerable range of nucleated cells and can propagate in the intermediate host. Yet, under the pressure of the immune system it transforms into an encysted persistent form residing primarily in the brain and muscle tissues. Encysted parasites, which are resistant to current medication, may reactivate and give rise to an acute infection. The clinical outcome of toxoplasmosis depends on a complex balance between the host immune response and parasite virulence factors. Susceptibility to the disease is thus determined by both parasite strains and host species. Recent advances on our understanding of host cell-parasite interactions and parasite virulence have brought new insights into the pathophysiology of T. gondii infection and are summarized here.
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Proximity-Labeling Reveals Novel Host and Parasite Proteins at the Toxoplasma Parasitophorous Vacuole Membrane. mBio 2021; 12:e0026021. [PMID: 34749525 PMCID: PMC8576527 DOI: 10.1128/mbio.00260-21] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii is a ubiquitous, intracellular parasite that envelops its parasitophorous vacuole with a protein-laden membrane (PVM). The PVM is critical for interactions with the infected host cell, such as nutrient transport and immune defense. Only a few parasite and host proteins have so far been identified on the host-cytosolic side of the Toxoplasma PVM. We report here the use of human foreskin fibroblasts expressing the proximity-labeling enzyme miniTurbo, fused to a domain that targets it to this face of the PVM, in combination with quantitative proteomics to specifically identify proteins present at this interface. Out of numerous human and parasite proteins with candidate PVM localization, we validate three parasite proteins (TGGT1_269950 [GRA61], TGGT1_215360 [GRA62], and TGGT1_217530 [GRA63]) and four new host proteins (PDCD6IP/ALIX, PDCD6, CC2D1A, and MOSPD2) as localized to the PVM in infected human cells through immunofluorescence microscopy. These results significantly expand our knowledge of proteins present at the Toxoplasma PVM and, given that three of the validated host proteins are components of the ESCRT (endosomal sorting complexes required for transport) machinery, they further suggest that novel biology is operating at this crucial host-pathogen interface.
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Frickel EM, Hunter CA. Lessons from Toxoplasma: Host responses that mediate parasite control and the microbial effectors that subvert them. J Exp Med 2021; 218:212714. [PMID: 34670268 PMCID: PMC8532566 DOI: 10.1084/jem.20201314] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/03/2021] [Accepted: 09/29/2021] [Indexed: 11/15/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii has long provided a tractable experimental system to investigate how the immune system deals with intracellular infections. This review highlights the advances in defining how this organism was first detected and the studies with T. gondii that contribute to our understanding of how the cytokine IFN-γ promotes control of vacuolar pathogens. In addition, the genetic tractability of this eukaryote organism has provided the foundation for studies into the diverse strategies that pathogens use to evade antimicrobial responses and now provides the opportunity to study the basis for latency. Thus, T. gondii remains a clinically relevant organism whose evolving interactions with the host immune system continue to teach lessons broadly relevant to host–pathogen interactions.
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Affiliation(s)
- Eva-Maria Frickel
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, UK
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
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Tomita T, Guevara RB, Shah LM, Afrifa AY, Weiss LM. Secreted Effectors Modulating Immune Responses to Toxoplasma gondii. Life (Basel) 2021; 11:988. [PMID: 34575137 PMCID: PMC8467511 DOI: 10.3390/life11090988] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/11/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite that chronically infects a third of humans. It can cause life-threatening encephalitis in immune-compromised individuals. Congenital infection also results in blindness and intellectual disabilities. In the intracellular milieu, parasites encounter various immunological effectors that have been shaped to limit parasite infection. Parasites not only have to suppress these anti-parasitic inflammatory responses but also ensure the host organism's survival until their subsequent transmission. Recent advancements in T. gondii research have revealed a plethora of parasite-secreted proteins that suppress as well as activate immune responses. This mini-review will comprehensively examine each secreted immunomodulatory effector based on the location of their actions. The first section is focused on secreted effectors that localize to the parasitophorous vacuole membrane, the interface between the parasites and the host cytoplasm. Murine hosts are equipped with potent IFNγ-induced immune-related GTPases, and various parasite effectors subvert these to prevent parasite elimination. The second section examines several cytoplasmic and ER effectors, including a recently described function for matrix antigen 1 (MAG1) as a secreted effector. The third section covers the repertoire of nuclear effectors that hijack transcription factors and epigenetic repressors that alter gene expression. The last section focuses on the translocation of dense-granule effectors and effectors in the setting of T. gondii tissue cysts (the bradyzoite parasitophorous vacuole).
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Affiliation(s)
- Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (T.T.); (R.B.G.)
| | - Rebekah B. Guevara
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (T.T.); (R.B.G.)
| | - Lamisha M. Shah
- Department of Biological Science, Lehman College of the City University of New York, Bronx, NY 10468, USA; (L.M.S.); (A.Y.A.)
| | - Andrews Y. Afrifa
- Department of Biological Science, Lehman College of the City University of New York, Bronx, NY 10468, USA; (L.M.S.); (A.Y.A.)
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (T.T.); (R.B.G.)
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Guo M, Sun J, Wang WT, Liu HY, Liu YH, Qin KR, Hu JR, Li XY, Liu HL, Wang W, Chen ZY, Wang CF, Wang HL. Toxoplasma gondii ROP17 promotes autophagy via the Bcl-2-Beclin 1 pathway. Folia Parasitol (Praha) 2021; 68. [PMID: 34180401 DOI: 10.14411/fp.2021.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 03/07/2021] [Indexed: 02/04/2023]
Abstract
The apicomplexan Toxoplasma gondii (Nicolle et Manceaux, 1908) secretes a group of serine/threonine kinases from rhoptries, which play vital roles in boosting intracellular infection. Toxoplasma gondii rhoptry organelle protein 17 (ROP17) is one of these important kinase proteins. Nevertheless, its function remains unclear. Here, we showed that ROP17 induced autophagy in vitro and in vivo. The autophagy of small intestine tissues of T. gondii tachyzoite (RH strain)-infected mice was detected by the immunohistochemistry staining of LC3B, Beclin 1 and P62. ROP17 overexpression augmented starvation-induced autophagy in HEK 293T cells as measured by MDC staining, transmission electron microscopy (TEM), fluorescence microscopy and Western blot analysis. Moreover, the interaction of ROP17 and Bcl-2 was confirmed using co-immunoprecipitation analysis, and the data demonstrated that ROP17 had an autophagic role dependent on the Beclin 1-Bcl-2 pathway, which was also revealed in an in vivo model through immunohistochemical staining. Pearson coefficient analysis showed that there existed strong positive correlations between the expression of ROP17 and LC3B, Beclin 1 and phosphorylation of Bcl-2, while strong negative correlations between the expression of ROP17 and p62 and Bcl-2. Collectively, our findings indicate that ROP17 plays a pivotal role in maintaining T. gondii proliferation in host cells via the promotion of autophagy-dependent survival.
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Affiliation(s)
- Min Guo
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China.,Labratory Animal Center, Shanxi Key Laboratory of Experimental Animal Science and Animal Model of Human Disease, Shanxi Medical University, Taiyuan,Shanxi, China.,Min Guo, Jia Sun and Wen-tao Wang contributed equally to this work *Address for correspondence: Hai-long Wang, ; Chun-fang Wang, ; Zhao-yang Chen, ; Address: School of Basic Medicine, Shanxi Medical University, No. 55, Wenhua Street, Jinzhong, Shanxi, 030600, China
| | - Jia Sun
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China.,Min Guo, Jia Sun and Wen-tao Wang contributed equally to this work *Address for correspondence: Hai-long Wang, ; Chun-fang Wang, ; Zhao-yang Chen, ; Address: School of Basic Medicine, Shanxi Medical University, No. 55, Wenhua Street, Jinzhong, Shanxi, 030600, China
| | - Wen-Tao Wang
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China.,Min Guo, Jia Sun and Wen-tao Wang contributed equally to this work *Address for correspondence: Hai-long Wang, ; Chun-fang Wang, ; Zhao-yang Chen, ; Address: School of Basic Medicine, Shanxi Medical University, No. 55, Wenhua Street, Jinzhong, Shanxi, 030600, China
| | - Hong-Yan Liu
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China.,Eugenics and Molecular Medicine Testing Center, Ulanqab Central Hospital, Wulanchabu, Neimenggu, China
| | - Yue-Hua Liu
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
| | - Ke-Ru Qin
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
| | - Jin-Rui Hu
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
| | - Xin-Yang Li
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
| | - Hong-Li Liu
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
| | - Wei Wang
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
| | - Zhao-Yang Chen
- Labratory Animal Center, Shanxi Key Laboratory of Experimental Animal Science and Animal Model of Human Disease, Shanxi Medical University, Taiyuan,Shanxi, China
| | - Chun-Fang Wang
- Labratory Animal Center, Shanxi Key Laboratory of Experimental Animal Science and Animal Model of Human Disease, Shanxi Medical University, Taiyuan,Shanxi, China
| | - Hai-Long Wang
- School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China
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Whole-genome sequencing of a Toxoplasma gondii strain from a Turkish isolate using next-generation sequencing technology. Acta Trop 2021; 218:105907. [PMID: 33789154 DOI: 10.1016/j.actatropica.2021.105907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/16/2021] [Accepted: 03/24/2021] [Indexed: 11/23/2022]
Abstract
PURPOSE Toxoplasma gondii is an intracellular parasite that can affect all vertebrae and is the causative agent of toxoplasmosis. At present, the United States CDC (Centers for Disease Control and Prevention) recognizes this infection as a neglected disease. Toxoplasma gondii infection profiles exhibit differences because of the different regional and climatic responses to these parasites in Turkey, and these protozoan infections are notably common in this country. In this study, we attempted to obtain the whole-genome sequence of T. gondii using next-generation sequencing technology. METHODS Toxoplasma gondii isolates were isolated from an infant with congenital toxoplasmosis by Ekmen et al. (1974) in Ankara, Turkey. Whole-genome sequencing (WGS) was performed using the Illumina HiSeq 2500 and HiSeq SBS Kit v2. A T. gondii library was created on this device in the initial stage. After the completion of the library phase, sequence analysis was begun with a next-generation sequencing device. The resulting fragments were combined using paired-end (PE) reading and converted into a single DNA fragment. Bioinformatic analysis was performed using the Geneious 2.1. PROGRAM RESULTS In our study, WGS was successfully performed on T. gondii. The T. gondii whole-genome sequence has a coverage value of 50x, a size of 61,5763 Mb and a GC ratio of 52.6%. Data from this sequence were submitted to the National Center for Biotechnology Information (NCBI) GenBank (www.ncbi.nlm.nih.gov) database under the name Toxoplasma gondii TR01 (TG_TR01). The accession number of the genome obtained in this study is WOEV00000000.1. The biological sample access number is SAMN13338796. The genome of the T. gondii strain obtained in this study was compared with the reference genome, and 8312 CDSs (coding sequences), 183 tRNAs, 294 rRNAs and 8789 genes were identified. Among the 8312 CDSs, 4284 encoded hypothetical proteins (hypothetical protein CDSs/proteins of unknown function). The entire genome sequence of T gondii TR01 was compared with that of Toxoplasma gondii ME49. The results of this comparison demonstrate that the analyzed genome was 99,98% similar to the reference genome. The accession numbers of 14 chromosomes belonging to the genome sequences of T. gondii TR01 (TG_TR01) are CM019722.1, CM019723.1, CM019724.1, CM019725.1, CM019726.1, CM019727.1, CM019728.1, CM019729.1, CM019730.1, CM019731.1, CM019732.1, CM019733.1, CM019734.1, and CM019735.1. CONCLUSION In this study, a whole-genome sequences of T. gondii was conducted for the first time in Turkey. The analyzed strain was named T. gondii TR01. The data obtained from this study may contribute to a better understanding of T. gondii. T. gondii is an important pathogen with an unusual population structure. Although T. gondii is highly zoonotic and has a complicated life cycle, some strains of this parasite have exhibited high genetic sequence similarity, and our study supports this knowlegde. The characterization of this strain may be very useful for the scientific community of our country and may help to establish a foundation for further research investigating the genome of T. gondii.
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Gaji RY, Sharp AK, Brown AM. Protein kinases in Toxoplasma gondii. Int J Parasitol 2021; 51:415-429. [PMID: 33581139 PMCID: PMC11065138 DOI: 10.1016/j.ijpara.2020.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/10/2020] [Accepted: 11/15/2020] [Indexed: 02/06/2023]
Abstract
Toxoplasma gondii is an obligatory intracellular pathogen that causes life threatening illness in immunodeficient individuals, miscarriage in pregnant woman, and blindness in newborn children. Similar to any other eukaryotic cell, protein kinases play critical and essential roles in the Toxoplasma life cycle. Accordingly, many studies have focused on identifying and defining the mechanism of function of these signalling proteins with a long-term goal to develop anti-Toxoplasma therapeutics. In this review, we briefly discuss classification and key components of the catalytic domain which are critical for functioning of kinases, with a focus on domains, families, and groups of kinases within Toxoplasma. More importantly, this article provides a comprehensive, current overview of research on kinase groups in Toxoplasma including the established eukaryotic AGC, CAMK, CK1, CMGC, STE, TKL families and the apicomplexan-specific FIKK, ROPK and WNG family of kinases. This work provides an overview and discusses current knowledge on Toxoplasma kinases including their localization, function, signalling network and role in acute and chronic pathogenesis, with a view towards the future in probing kinases as viable drug targets.
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Affiliation(s)
- Rajshekhar Y Gaji
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech University, Blacksburg, VA, USA; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
| | - Amanda K Sharp
- Interdisciplinary Program in Genetics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, VA, USA
| | - Anne M Brown
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA; University Libraries, Virginia Tech, Blacksburg, VA, USA
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Ihara F, Nishikawa Y. Toxoplasma gondii manipulates host cell signaling pathways via its secreted effector molecules. Parasitol Int 2021; 83:102368. [PMID: 33905814 DOI: 10.1016/j.parint.2021.102368] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/13/2021] [Accepted: 04/07/2021] [Indexed: 01/07/2023]
Abstract
The obligate intracellular parasite Toxoplasma gondii secretes a vast variety of effector molecules from organelles known as rhoptries (ROPs) and dense granules (GRAs). ROP proteins are released into the cytosol of the host cell where they are directed to the cell nucleus or to the parasitophorous vacuole (PV) membrane. ROPs secrete proteins that enable host cell penetration and vacuole formation by the parasites, as well as hijacking host-immune responses. After invading host cells, T. gondii multiplies within a PV that is maintained by the parasite proteins secreted from GRAs. Most GRA proteins remain within the PV, but some are known to access the host cytosol across the PV membrane, and a few are able to traffic into the host-cell nucleus. These effectors bind to host cell proteins and affect host cell signaling pathways to favor the parasite. Studies on host-pathogen interactions have identified many infection-altered host signal transductions. Notably, the relationship between individual parasite effector molecules and the specific targeting of host-signaling pathways is being elucidated through the advent of forward and reverse genetic strategies. Understanding the complex nature of the host-pathogen interactions underlying how the host-signaling pathway is manipulated by parasite effectors may lead to new molecular biological knowledge and novel therapeutic methods for toxoplasmosis. In this review, we discuss how T. gondii modulates cell signaling pathways in the host to favor its survival.
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Affiliation(s)
- Fumiaki Ihara
- Molecular Parasitology Section, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States.
| | - Yoshifumi Nishikawa
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
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31
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Abstract
Obligate intracellular malaria parasites reside within a vacuolar compartment generated during invasion which is the principal interface between pathogen and host. To subvert their host cell and support their metabolism, these parasites coordinate a range of transport activities at this membrane interface that are critically important to parasite survival and virulence, including nutrient import, waste efflux, effector protein export, and uptake of host cell cytosol. Here, we review our current understanding of the transport mechanisms acting at the malaria parasite vacuole during the blood and liver-stages of development with a particular focus on recent advances in our understanding of effector protein translocation into the host cell by the Plasmodium Translocon of EXported proteins (PTEX) and small molecule transport by the PTEX membrane-spanning pore EXP2. Comparison to Toxoplasma gondii and other related apicomplexans is provided to highlight how similar and divergent mechanisms are employed to fulfill analogous transport activities.
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Affiliation(s)
- Josh R. Beck
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Chi-Min Ho
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
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32
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Panas MW, Boothroyd JC. Seizing control: How dense granule effector proteins enable Toxoplasma to take charge. Mol Microbiol 2021; 115:466-477. [PMID: 33400323 PMCID: PMC8344355 DOI: 10.1111/mmi.14679] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/02/2021] [Accepted: 01/03/2021] [Indexed: 12/24/2022]
Abstract
Control of the host cell is crucial to the Apicomplexan parasite, Toxoplasma gondii, while it grows intracellularly. To achieve this goal, these single-celled eukaryotes export a series of effector proteins from organelles known as "dense granules" that interfere with normal cellular processes and responses to invasion. While some effectors are found attached to the outer surface of the parasitophorous vacuole (PV) in which Toxoplasma tachyzoites reside, others are found in the host cell's cytoplasm and yet others make their way into the host nucleus, where they alter host transcription. Among the processes that are severely altered are innate immune responses, host cell cycle, and association with host organelles. The ways in which these crucial processes are altered through the coordinated action of a large collection of effectors is as elegant as it is complex, and is the central focus of the following review; we also discuss the recent advances in our understanding of how dense granule effector proteins are trafficked out of the PV.
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Affiliation(s)
- Michael W. Panas
- Dept. Microbiology and Immunology, Stanford University School of Medicine, Stanford CA 94305
| | - John C. Boothroyd
- Dept. Microbiology and Immunology, Stanford University School of Medicine, Stanford CA 94305
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33
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Mukhopadhyay D, Arranz-Solís D, Saeij JPJ. Influence of the Host and Parasite Strain on the Immune Response During Toxoplasma Infection. Front Cell Infect Microbiol 2020; 10:580425. [PMID: 33178630 PMCID: PMC7593385 DOI: 10.3389/fcimb.2020.580425] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/11/2020] [Indexed: 01/02/2023] Open
Abstract
Toxoplasma gondii is an exceptionally successful parasite that infects a very broad host range, including humans, across the globe. The outcome of infection differs remarkably between hosts, ranging from acute death to sterile infection. These differential disease patterns are strongly influenced by both host- and parasite-specific genetic factors. In this review, we discuss how the clinical outcome of toxoplasmosis varies between hosts and the role of different immune genes and parasite virulence factors, with a special emphasis on Toxoplasma-induced ileitis and encephalitis.
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Affiliation(s)
| | | | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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34
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Wang Y, Sangaré LO, Paredes-Santos TC, Saeij JPJ. Toxoplasma Mechanisms for Delivery of Proteins and Uptake of Nutrients Across the Host-Pathogen Interface. Annu Rev Microbiol 2020; 74:567-586. [PMID: 32680452 PMCID: PMC9934516 DOI: 10.1146/annurev-micro-011720-122318] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many intracellular pathogens, including the protozoan parasite Toxoplasma gondii, live inside a vacuole that resides in the host cytosol. Vacuolar residence provides these pathogens with a defined niche for replication and protection from detection by host cytosolic pattern recognition receptors. However, the limiting membrane of the vacuole, which constitutes the host-pathogen interface, is also a barrier for pathogen effectors to reach the host cytosol and for the acquisition of host-derived nutrients. This review provides an update on the specialized secretion and trafficking systems used by Toxoplasma to overcome the barrier of the parasitophorous vacuole membrane and thereby allow the delivery of proteins into the host cell and the acquisition of host-derived nutrients.
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Affiliation(s)
- Yifan Wang
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA; , , ,
| | - Lamba Omar Sangaré
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA; , , ,
| | - Tatiana C. Paredes-Santos
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
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35
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Kongsomboonvech AK, Rodriguez F, Diep AL, Justice BM, Castallanos BE, Camejo A, Mukhopadhyay D, Taylor GA, Yamamoto M, Saeij JPJ, Reese ML, Jensen KDC. Naïve CD8 T cell IFNγ responses to a vacuolar antigen are regulated by an inflammasome-independent NLRP3 pathway and Toxoplasma gondii ROP5. PLoS Pathog 2020; 16:e1008327. [PMID: 32853276 PMCID: PMC7480859 DOI: 10.1371/journal.ppat.1008327] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 09/09/2020] [Accepted: 07/05/2020] [Indexed: 12/31/2022] Open
Abstract
Host resistance to Toxoplasma gondii relies on CD8 T cell IFNγ responses, which if modulated by the host or parasite could influence chronic infection and parasite transmission between hosts. Since host-parasite interactions that govern this response are not fully elucidated, we investigated requirements for eliciting naïve CD8 T cell IFNγ responses to a vacuolar resident antigen of T. gondii, TGD057. Naïve TGD057 antigen-specific CD8 T cells (T57) were isolated from transnuclear mice and responded to parasite-infected bone marrow-derived macrophages (BMDMs) in an antigen-dependent manner, first by producing IL-2 and then IFNγ. T57 IFNγ responses to TGD057 were independent of the parasite’s protein export machinery ASP5 and MYR1. Instead, host immunity pathways downstream of the regulatory Immunity-Related GTPases (IRG), including partial dependence on Guanylate-Binding Proteins, are required. Multiple T. gondii ROP5 isoforms and allele types, including ‘avirulent’ ROP5A from clade A and D parasite strains, were able to suppress CD8 T cell IFNγ responses to parasite-infected BMDMs. Phenotypic variance between clades B, C, D, F, and A strains suggest T57 IFNγ differentiation occurs independently of parasite virulence or any known IRG-ROP5 interaction. Consistent with this, removal of ROP5 is not enough to elicit maximal CD8 T cell IFNγ production to parasite-infected cells. Instead, macrophage expression of the pathogen sensors, NLRP3 and to a large extent NLRP1, were absolute requirements. Other members of the conventional inflammasome cascade are only partially required, as revealed by decreased but not abrogated T57 IFNγ responses to parasite-infected ASC, caspase-1/11, and gasdermin D deficient cells. Moreover, IFNγ production was only partially reduced in the absence of IL-12, IL-18 or IL-1R signaling. In summary, T. gondii effectors and host machinery that modulate parasitophorous vacuolar membranes, as well as NLR-dependent but inflammasome-independent pathways, determine the full commitment of CD8 T cells IFNγ responses to a vacuolar antigen. Parasites are excellent “students” of our immune system as they can deflect, antagonize and confuse the immune response making it difficult to vaccinate against these pathogens. In this report, we analyzed how a widespread parasite of mammals, Toxoplasma gondii, manipulates an immune cell needed for immunity to many intracellular pathogens, the CD8 T cell. Host pathways that govern CD8 T cell production of the immune protective cytokine, IFNγ, were also explored. We hypothesized the secreted T. gondii virulence factor, ROP5, work to inhibit the MHC 1 antigen presentation pathway therefore making it difficult for CD8 T cells to see T. gondii antigens sequestered inside a parasitophorous vacuole. However, manipulation through T. gondii ROP5 does not fully explain how CD8 T cells commit to making IFNγ in response to infection. Importantly, CD8 T cell IFNγ responses to T. gondii require the pathogen sensor NLRP3 to be expressed in the infected cell. Other proteins associated with NLRP3 activation, including members of the conventional inflammasome activation cascade pathway, are only partially involved. Our results identify a novel pathway by which NLRP3 regulates T cell function and underscore the need for NLRP3-activating adjuvants in vaccines aimed at inducing CD8 T cell IFNγ responses to parasites.
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Affiliation(s)
- Angel K. Kongsomboonvech
- Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Felipe Rodriguez
- Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Anh L. Diep
- Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Brandon M. Justice
- Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Brayan E. Castallanos
- Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
| | - Ana Camejo
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Debanjan Mukhopadhyay
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Gregory A. Taylor
- Departments of Medicine; Molecular Genetics and Microbiology; and Immunology; and Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, United States of America
- Geriatric Research, Education, and Clinical Center, Durham VA Health Care System, Durham, North Carolina, United States of America
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Jeroen P. J. Saeij
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Michael L. Reese
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, Texas, United States of America
| | - Kirk D. C. Jensen
- Department of Molecular and Cell Biology, University of California, Merced, Merced, California, United States of America
- Health Sciences Research Institute, University of California, Merced, Merced, California, United States of America
- * E-mail:
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Abstract
Manipulation of the host cell is a crucial part of life for many intracellular organisms. We have recently come to appreciate the extent to which the intracellular pathogen Toxoplasma gondii reprograms its host cell, and this is illustrated by the marked upregulation of the central regulator c-Myc, an oncogene that coordinates myriad cellular functions. In an effort to identify an effector protein capable of regulating c-Myc, our laboratory constructed a screen for mutant parasites unable to accomplish this upregulation. Interestingly, this screen identified numerous components of a complex located in/on the parasitophorous vacuole membrane necessary to translocate Toxoplasma proteins out into the host cytosol, but it never identified a specific effector protein. Thus, how the parasite upregulates c-Myc has largely been a mystery. Previously, the Toxoplasma dense granule protein GRA16 has been described to bind to one isoform of PP2A-B, a regulatory subunit that coordinates the activity of the catalytic protein phosphatase PP2A. As other PP2A subunits have been reported to target PP2A protein phosphatase activity to c-Myc, subsequently leading to c-Myc destabilization, we examined whether GRA16 has an impact on host c-Myc accumulation. Expression of Toxoplasma's GRA16 protein in Neospora caninum, a close relative of Toxoplasma that does not naturally upregulate host c-Myc, conferred the ability on Neospora to do this now. Further support was obtained by deleting the GRA16 gene from Toxoplasma and observing a severely diminished ability of Toxoplasma tachyzoites to upregulate host c-Myc. Thus, GRA16 is an effector protein central to Toxoplasma's ability to upregulate host c-Myc.IMPORTANCE The proto-oncogene c-Myc plays a crucial role in the growth and division of many animal cells. Previous studies have identified an active upregulation of c-Myc by Toxoplasma tachyzoites, suggesting the existence of one or more exported "effector" proteins. The identity of such an effector, however, has not previously been known. Here, we show that a previously known secreted protein, GRA16, plays a crucial role in c-Myc upregulation. This finding will enable further dissection of the precise mechanism and role of c-Myc upregulation in Toxoplasma-infected cells.
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Affiliation(s)
- Michael W Panas
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - John C Boothroyd
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
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Crossing the Vacuolar Rubicon: Structural Insights into Effector Protein Trafficking in Apicomplexan Parasites. Microorganisms 2020; 8:microorganisms8060865. [PMID: 32521667 PMCID: PMC7355975 DOI: 10.3390/microorganisms8060865] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022] Open
Abstract
Apicomplexans form a large phylum of parasitic protozoa, including the genera Plasmodium, Toxoplasma, and Cryptosporidium, the causative agents of malaria, toxoplasmosis, and cryptosporidiosis, respectively. They cause diseases not only in humans but also in animals, with dramatic consequences in agriculture. Most apicomplexans are vacuole-dwelling and obligate intracellular parasites; as they invade the host cell, they become encased in a parasitophorous vacuole (PV) derived from the host cellular membrane. This creates a parasite-host interface that acts as a protective barrier but also constitutes an obstacle through which the pathogen must import nutrients, eliminate wastes, and eventually break free upon egress. Completion of the parasitic life cycle requires intense remodeling of the infected host cell. Host cell subversion is mediated by a subset of essential effector parasitic proteins and virulence factors actively trafficked across the PV membrane. In the malaria parasite Plasmodium, a unique and highly specialized ATP-driven vacuolar secretion system, the Plasmodium translocon of exported proteins (PTEX), transports effector proteins across the vacuolar membrane. Its core is composed of the three essential proteins EXP2, PTEX150, and HSP101, and is supplemented by the two auxiliary proteins TRX2 and PTEX88. Many but not all secreted malarial effector proteins contain a vacuolar trafficking signal or Plasmodium export element (PEXEL) that requires processing by an endoplasmic reticulum protease, plasmepsin V, for proper export. Because vacuolar parasitic protein export is essential to parasite survival and virulence, this pathway is a promising target for the development of novel antimalarial therapeutics. This review summarizes the current state of structural and mechanistic knowledge on the Plasmodium parasitic vacuolar secretion and effector trafficking pathway, describing its most salient features and discussing the existing differences and commonalities with the vacuolar effector translocation MYR machinery recently described in Toxoplasma and other apicomplexans of significance to medical and veterinary sciences.
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Mayoral J, Shamamian P, Weiss LM. In Vitro Characterization of Protein Effector Export in the Bradyzoite Stage of Toxoplasma gondii. mBio 2020; 11:e00046-20. [PMID: 32156805 PMCID: PMC7064745 DOI: 10.1128/mbio.00046-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 01/23/2020] [Indexed: 12/16/2022] Open
Abstract
The ubiquitous parasite Toxoplasma gondii exhibits an impressive ability to maintain chronic infection of its host for prolonged periods. Despite this, little is known regarding whether and how T. gondii bradyzoites, a quasi-dormant life stage residing within intracellular cysts, manipulate the host cell to maintain persistent infection. A previous proteomic study of the cyst wall, an amorphous layer of proteins that forms underneath the cyst membrane, identified MYR1 as a putative cyst wall protein in vitro Because MYR1 is known to be involved in the translocation of parasite-derived effector proteins into the host cell, we sought to determine whether parasites transitioning toward the bradyzoite life stage retain the capacity to translocate proteins via this pathway. By epitope tagging the endogenous loci of four known effectors that translocate from the parasitophorous vacuole into the host cell nucleus, we show, by immunofluorescence assays, that most effectors accumulate in the host nucleus at early but not late time points after infection, during the tachyzoite-to-bradyzoite transition and when parasites further along the bradyzoite differentiation continuum invade a new host cell. We demonstrate that the suppression of interferon gamma signaling, which was previously shown to be mediated by the effector TgIST, also occurs in the context of prolonged infection with bradyzoites and that TgIST export is a process that occurs beyond the early stages of host cell infection. These findings have important implications regarding how this highly successful parasite maintains persistent infection of its host.IMPORTANCEToxoplasma bradyzoites persist within tissue cysts and are refractory to current treatments, serving as a reservoir for acute complications in settings of compromised immunity. Much remains to be understood regarding how this life stage successfully establishes and maintains persistent infection. In this study, we investigated whether the export of parasite effector proteins into the host cell occurs during the development of in vitro tissue cysts. We quantified the presence of four previously described effectors in host cell nuclei at different time points after bradyzoite differentiation and found that they accumulated largely during the early stages of infection. Despite a decline in nuclear accumulation, we found that one of these effectors still mediated its function after prolonged infection with bradyzoites, and we provide evidence that this effector is exported beyond early infection stages. These findings suggest that effector export from within developing tissue cysts provides one potential mechanism by which this parasite achieves chronic infection.
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Affiliation(s)
- Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Peter Shamamian
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, New York, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, New York, New York, USA
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Cygan AM, Theisen TC, Mendoza AG, Marino ND, Panas MW, Boothroyd JC. Coimmunoprecipitation with MYR1 Identifies Three Additional Proteins within the Toxoplasma gondii Parasitophorous Vacuole Required for Translocation of Dense Granule Effectors into Host Cells. mSphere 2020; 5:e00858-19. [PMID: 32075880 PMCID: PMC7031616 DOI: 10.1128/msphere.00858-19] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/24/2020] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is a ubiquitous, intracellular protozoan that extensively modifies infected host cells through secreted effector proteins. Many such effectors must be translocated across the parasitophorous vacuole (PV), in which the parasites replicate, ultimately ending up in the host cytosol or nucleus. This translocation has previously been shown to be dependent on five parasite proteins: MYR1, MYR2, MYR3, ROP17, and ASP5. We report here the identification of several MYR1-interacting and novel PV-localized proteins via affinity purification of MYR1, including TGGT1_211460 (dubbed MYR4), TGGT1_204340 (dubbed GRA54), and TGGT1_270320 (PPM3C). Further, we show that three of the MYR1-interacting proteins, GRA44, GRA45, and MYR4, are essential for the translocation of the Toxoplasma effector protein GRA16 and for the upregulation of human c-Myc and cyclin E1 in infected cells. GRA44 and GRA45 contain ASP5 processing motifs, but like MYR1, processing at these sites appears to be nonessential for their role in protein translocation. These results expand our understanding of the mechanism of effector translocation in Toxoplasma and indicate that the process is highly complex and dependent on at least eight discrete proteins.IMPORTANCEToxoplasma is an extremely successful intracellular parasite and important human pathogen. Upon infection of a new cell, Toxoplasma establishes a replicative vacuole and translocates parasite effectors across this vacuole to function from the host cytosol and nucleus. These effectors play a key role in parasite virulence. The work reported here newly identifies three parasite proteins that are necessary for protein translocation into the host cell. These results significantly increase our knowledge of the molecular players involved in protein translocation in Toxoplasma-infected cells and provide additional potential drug targets.
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Affiliation(s)
- Alicja M Cygan
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Terence C Theisen
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Alma G Mendoza
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Nicole D Marino
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Michael W Panas
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - John C Boothroyd
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
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40
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Blakely WJ, Holmes MJ, Arrizabalaga G. The Secreted Acid Phosphatase Domain-Containing GRA44 from Toxoplasma gondii Is Required for c-Myc Induction in Infected Cells. mSphere 2020; 5:e00877-19. [PMID: 32075881 PMCID: PMC7031617 DOI: 10.1128/msphere.00877-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/24/2020] [Indexed: 11/20/2022] Open
Abstract
During host cell invasion, the eukaryotic pathogen Toxoplasma gondii forms a parasitophorous vacuole to safely reside within the cell, while it is partitioned from host cell defense mechanisms. From within this safe niche, parasites sabotage multiple host cell systems, including gene expression, apoptosis, and intracellular immune recognition, by secreting a large arsenal of effector proteins. Many parasite proteins studied for active host cell manipulative interactions have been kinases. The translocation of effectors from the parasitophorous vacuole into the host cell is mediated by a putative translocon complex, which includes the proteins MYR1, MYR2, and MYR3. Whether other proteins are involved in the structure or regulation of this putative translocon is not known. We have discovered that the secreted protein GRA44, which contains a putative acid phosphatase domain, interacts with members of this complex and is required for host cell effects downstream of effector secretion. We have determined that GRA44 is processed in a region with homology to sequences targeted by protozoan proteases of the secretory pathway and that both major cleavage fragments are secreted into the parasitophorous vacuole. Immunoprecipitation experiments showed that GRA44 interacts with a large number of secreted proteins, including MYR1. Importantly, conditional knockdown of GRA44 resulted in a lack of host cell c-Myc upregulation, which mimics the phenotype seen when members of the translocon complex are genetically disrupted. Thus, the putative acid phosphatase GRA44 is crucial for host cell alterations during Toxoplasma infection and is associated with the translocon complex which Toxoplasma relies upon for success as an intracellular pathogen.IMPORTANCE Approximately one-third of humans are infected with the parasite Toxoplasma gondiiToxoplasma infections can lead to severe disease in those with a compromised or suppressed immune system. Additionally, infections during pregnancy present a significant health risk to the developing fetus. Drugs that target this parasite are limited, have significant side effects, and do not target all disease stages. Thus, a thorough understanding of how the parasite propagates within a host is critical in the discovery of novel therapeutic targets. Toxoplasma replication requires that it enter the cells of the infected organism. In order to survive the environment inside a cell, Toxoplasma secretes a large repertoire of proteins, which hijack a number of important cellular functions. How these Toxoplasma proteins move from the parasite into the host cell is not well understood. Our work shows that the putative phosphatase GRA44 is part of a protein complex responsible for this process.
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Affiliation(s)
- William J Blakely
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michael J Holmes
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Gustavo Arrizabalaga
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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41
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Guevara RB, Fox BA, Bzik DJ. Toxoplasma gondii Parasitophorous Vacuole Membrane-Associated Dense Granule Proteins Regulate Maturation of the Cyst Wall. mSphere 2020; 5:e00851-19. [PMID: 31941814 PMCID: PMC6968655 DOI: 10.1128/msphere.00851-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/19/2019] [Indexed: 11/20/2022] Open
Abstract
After differentiation is triggered, the tachyzoite-stage Toxoplasma gondii parasitophorous vacuole membrane (PVM) has been hypothesized to transition into the cyst membrane that surrounds the cyst wall and encloses bradyzoites. Here, we tracked the localization of two PVM dense granule (GRA) proteins (GRA5 and GRA7) after in vitro differentiation of the tachyzoite stage parasitophorous vacuole into the mature cyst. GRA5 and GRA7 were visible at the cyst periphery at 6 h and at all later times after differentiation, suggesting that the PVM remained intact as it transitioned into the cyst membrane. By day 3 postdifferentiation, GRA5 and GRA7 were visible in a continuous pattern at the cyst periphery. In mature 7- and 10-day-old cysts permeabilized with a saponin pulse, GRA5 and GRA7 were localized to the cyst membrane and the cyst wall regions. Cysts at different stages of cyst development exhibited differential susceptibility to saponin permeabilization, and, correspondingly, saponin selectively removed GRA5 from the cyst membrane and cyst wall region in 10-day-old cysts. GRA5 and GRA7 were localized at the cyst membrane and cyst wall region at all times after differentiation of the parasitophorous vacuole, which supports a previous model proposing that the PVM develops into the cyst membrane. In addition, evaluation of Δgra3, Δgra5, Δgra7, Δgra8, and Δgra14 mutants revealed that PVM-localized GRAs were crucial to support the normal rate of accumulation of cyst wall proteins at the cyst periphery.IMPORTANCEToxoplasma gondii establishes chronic infection in humans by forming thick-walled cysts that persist in the brain. Once host immunity wanes, cysts reactivate to cause severe, and often lethal, toxoplasmic encephalitis. There is no available therapy to eliminate cysts or to prevent their reactivation. Furthermore, how the cyst membrane and cyst wall structures develop is poorly understood. Here, we visualized and tracked the localization of Toxoplasma parasitophorous vacuole membrane (PVM) dense granules (GRA) proteins during cyst development in vitro. PVM-localized GRA5 and GRA7 were found at the cyst membrane and cyst wall region throughout cyst development, suggesting that the PVM remains intact and develops into the cyst membrane. In addition, our results show that genetic deletion of PVM GRAs reduced the rate of accumulation of cyst wall cargo at the cyst periphery and suggest that PVM-localized GRAs mediate the development and maturation of the cyst wall and cyst membrane.
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Affiliation(s)
- Rebekah B Guevara
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Barbara A Fox
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - David J Bzik
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
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Paredes-Santos T, Wang Y, Waldman B, Lourido S, Saeij JP. The GRA17 Parasitophorous Vacuole Membrane Permeability Pore Contributes to Bradyzoite Viability. Front Cell Infect Microbiol 2019; 9:321. [PMID: 31572690 PMCID: PMC6751312 DOI: 10.3389/fcimb.2019.00321] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 08/27/2019] [Indexed: 01/25/2023] Open
Abstract
The Toxoplasma gondii parasitophorous vacuole membrane (PVM) offers protection from the host immune system but is also a barrier for uptake of nutrients from the host. Previously, we showed that GRA17 mediates the tachyzoite PVM permeability to small molecules. During the conversion from tachyzoites to encysted bradyzoites, the PVM become the cyst membrane that is the outer layer of the cyst wall. Little is known about how small molecules, such as nutrients, enter cysts. To characterize GRA17's role in cysts, we deleted GRA17 in the type II ME49 cyst-forming strain. ME49Δgra17 parasites have reduced growth and formed grossly enlarged "bubble vacuoles," which have reduced PVM small molecule permeability. ME49Δgra17 parasites formed cysts in vitro at rates comparable to the wild-type, but the viability of the bradyzoites inside these cysts was significantly reduced compared to wild-type bradyzoites. Genetic complementation of ME49Δgra17 with GRA17 expressed from the endogenous or tachyzoite-specific SAG1 promoter recovered the viability of bradyzoites. Complementation with the bradyzoite-specific SRS9 promoter drastically increased the viability of bradyzoites, demonstrating the importance of GRA17 in regulating bradyzoite viability inside cysts. Mice infected with a high dose of ME49Δgra17 parasites did not contain parasites in their brain nor did mice infected with ME49Δgra17 complemented with GRA17 expressed from a bradyzoite-specific promoter. Our results suggest that the ME49Δgra17 strain is avirulent and is cleared before it can reach the brain and that GRA17 not only plays an important role during acute infections but is also needed for viability of bradyzoites inside cysts.
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Affiliation(s)
- Tatiana Paredes-Santos
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
| | - Yifan Wang
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
| | - Benjamin Waldman
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jeroen P. Saeij
- Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA, United States
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43
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Young J, Dominicus C, Wagener J, Butterworth S, Ye X, Kelly G, Ordan M, Saunders B, Instrell R, Howell M, Stewart A, Treeck M. A CRISPR platform for targeted in vivo screens identifies Toxoplasma gondii virulence factors in mice. Nat Commun 2019; 10:3963. [PMID: 31481656 PMCID: PMC6722137 DOI: 10.1038/s41467-019-11855-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/07/2019] [Indexed: 02/08/2023] Open
Abstract
Genome-wide CRISPR screening is a powerful tool to identify genes required under selective conditions. However, the inherent scale of genome-wide libraries can limit their application in experimental settings where cell numbers are restricted, such as in vivo infections or single cell analysis. The use of small scale CRISPR libraries targeting gene subsets circumvents this problem. Here we develop a method for rapid generation of custom guide RNA (gRNA) libraries using arrayed single-stranded oligonucleotides for reproducible pooled cloning of CRISPR/Cas9 libraries. We use this system to generate mutant pools of different sizes in the protozoan parasite Toxoplasma gondi and describe optimised analysis methods for small scale libraries. An in vivo genetic screen in the murine host identifies novel and known virulence factors and we confirm results using cloned knock-out parasites. Our study also reveals a potential trans-rescue of individual knock-out parasites in pools of mutants compared to homogenous knock-out lines of the key virulence factor MYR1.
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Affiliation(s)
- Joanna Young
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Caia Dominicus
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Jeanette Wagener
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Simon Butterworth
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Xingda Ye
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Gavin Kelly
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Merav Ordan
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Becky Saunders
- High Throughput Screening Science Technology Platform, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Rachael Instrell
- High Throughput Screening Science Technology Platform, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Michael Howell
- High Throughput Screening Science Technology Platform, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Aengus Stewart
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK.
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44
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Translocation of effector proteins into host cells by Toxoplasma gondii. Curr Opin Microbiol 2019; 52:130-138. [PMID: 31446366 DOI: 10.1016/j.mib.2019.07.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022]
Abstract
The Apicomplexan parasite, Toxoplasma gondii, is an obligate intracellular organism that must co-opt its host cell to survive. To this end, Toxoplasma parasites introduce a suite of effector proteins from two secretory compartments called rhoptries and dense granules into the host cells. Once inside, these effectors extensively modify the host cell to facilitate parasite penetration, replication and persistence. In this review, we summarize the most recent advances in current understanding of effector translocation from Toxoplasma's rhoptry and dense granule organelles into the host cell, with comparisons to Plasmodium spp. for broader context.
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45
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Neighbors Working Together: a Toxoplasma Rhoptry Protein That Facilitates Dense Granule Protein Translocation into the Host Cell. mSphere 2019; 4:4/4/e00523-19. [PMID: 31366706 PMCID: PMC6669340 DOI: 10.1128/msphere.00523-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The opportunistic pathogen Toxoplasma gondii is highly adept at manipulating host cell functions. While inside a host cell, Toxoplasma divides within a parasitophorous vacuole from which it secretes numerous effector proteins from its dense granules. Many of these so-called GRA proteins are translocated from the parsitophorous vacuole into the host cell where they directly disrupt host signaling pathways. The opportunistic pathogen Toxoplasma gondii is highly adept at manipulating host cell functions. While inside a host cell, Toxoplasma divides within a parasitophorous vacuole from which it secretes numerous effector proteins from its dense granules. Many of these so-called GRA proteins are translocated from the parsitophorous vacuole into the host cell where they directly disrupt host signaling pathways. The machinery that drives the translocation of GRA proteins across the parasitophorous vacuole membrane is being elucidated through both genetic and biochemical approaches. A new mSphere research article (M. W. Panas, A. Ferrel, A. Naor, E. Tenborg, et al., mSphere 4:e00276-19, 2019, https://doi.org/10.1128/mSphere.00276-19) describes how the kinase ROP17, which is secreted from the parasite’s rhoptries into the host cell during invasion, regulates the translocation of GRA effectors.
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46
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Drewry LL, Jones NG, Wang Q, Onken MD, Miller MJ, Sibley LD. The secreted kinase ROP17 promotes Toxoplasma gondii dissemination by hijacking monocyte tissue migration. Nat Microbiol 2019; 4:1951-1963. [PMID: 31332383 PMCID: PMC6814536 DOI: 10.1038/s41564-019-0504-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 06/05/2019] [Indexed: 01/02/2023]
Abstract
The protozoan parasite Toxoplasma gondii is thought to exploit monocyte trafficking to facilitate dissemination across endothelial barriers such as the blood-brain barrier. Here we analyzed the migration of parasitized monocytes in model endothelial and interstitial environments. We report that infection enhanced monocyte locomotion on the surface of endothelial cells, but profoundly inhibited monocyte transmigration across endothelial barriers. In contrast, infection robustly increased monocyte and macrophage migration through collagen-rich tissues in a Rho/ROCK-dependent manner consistent with integrin-independent interstitial migration. We further demonstrated that the secreted T. gondii protein kinase ROP17 was required for enhanced tissue migration. In vivo, ROP17-deficient parasites failed to upregulate monocyte tissue migration and exhibited an early dissemination delay, leading to prolonged mouse survival. Our findings indicate that the parasite-induced changes in monocyte motility likely facilitate the transport of T. gondii through tissues and promote systemic dissemination, rather than shuttle parasites across the blood-brain barrier via extravasation.
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Affiliation(s)
- Lisa L Drewry
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nathaniel G Jones
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.,York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Quiling Wang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael D Onken
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Mark J Miller
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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Drewry LL, Sibley LD. The hitchhiker's guide to parasite dissemination. Cell Microbiol 2019; 21:e13070. [PMID: 31219666 DOI: 10.1111/cmi.13070] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/21/2019] [Accepted: 06/13/2019] [Indexed: 12/29/2022]
Abstract
Toxoplasma gondii (T. gondii) is a parasitic protist that can infect nearly all nucleated cell types and tissues of warm-blooded vertebrate hosts. T. gondii utilises a unique form of gliding motility to cross cellular barriers, enter tissues, and penetrate host cells, thus enhancing spread within an infected host. However, T. gondii also disseminates by hijacking the migratory abilities of infected leukocytes. Traditionally, this process has been viewed as a route to cross biological barriers such as the blood-brain barrier. Here, we review recent findings that challenge this view by showing that infection of monocytes downregulates the program of transendothelial migration. Instead, infection by T. gondii enhances Rho-dependent interstitial migration of monocytes and macrophages, which enhances dissemination within tissues. Collectively, the available evidence indicates that T. gondii parasites use multiple means to disseminate within the host, including enhanced motility in tissues and translocation across biological barriers.
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Affiliation(s)
- Lisa L Drewry
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
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